(English Medium) ICSE Class 10 - CISCE Question Bank Solutions

Explain briefly what causes the twinkling of stars at night.

Can the absolute refractive index of a medium be less than one?

Why does the sun appear bigger during sunset or sunrise?

What is the total reflecting prism?

Name two instruments of the total refracting prism in which is used.

In what condition a prism is said to be in the position of minimum deviation? What is the direction of the refracted ray inside the prism in this condition?

How does the angle of deviation produced by a prism depend on the colour of light used? Which colour of white light is deviated (i) most, (ii) least, by a prism?

What do you understand by the deviation produced by a prism?

You are provided with a printed piece of paper. Using this paper how will you differentiate between a convex lens and a concave lens?

The refractive index of air with respect to glass is defined: as _gµ_a = sin i/sin r
Write down a similar expression for _aµ_g in terms of angle i and r.

The refractive index of air with respect to glass is defined: as _gµ_a = sin i/sin r
If r = 90°, what is the corresponding angle i called?

A ray of light moves from a rare medium to a dense medium as shown in the diagram below. Write down the number of the ray which represents the partially reflected ray.

In the diagram below, PQ is a ray of light incident on a rectangular glass block.

Copy the diagram and complete the path of the ray of light through the glass block. In your diagram, mark the angle of incidence by letter ‘i’ and the angle of emergence by the letter ‘e’.

In the diagram below, PQ is a ray of light incident on a rectangular glass block.

How are the angles ‘i’ and ‘e’ related to each other?

A ray of monochromatic light is incident from air into a glass slab. Draw a labelled ray diagram indicating the change in its path till it emerges out of the slab. In the diagram, mark the angle of incidence (i) and the angle of refraction (r) at the first interface. How is the refractive index of glass related to the angles i and r?

Draw ray of light bending towards the normal while passing from air to glass. Label your diagrams.

Draw ray of light bending towards the normal while passing from glass to water. Label your diagrams.

After a robbery, if a window has been broken, there will be tiny particles of glass. Some of these will be found at the scene of the crime and some may be caught in the thief’s clothing. If the police can prove that these particles are identical, they have a strong case.
A method of doing this is to suspend the particles of glass in a special liquid. Light of a single colour is thrown through the liquid and the particles viewed through a microscope. The temperature of the liquid is then slowly altered. This alters the speed of light through the liquid (i.e., it alters the refractive index). At one particular temperature, the particles of glass disappear. It this happens at the same temperature for both sets of glass particles, they probably came from the same broken pane of glass.
Complete and copy the diagram to show how light bends when it travels from the liquid to the glass and back to the liquid, If the light slows down in the glass.

The figure shows two prisms A and B. A monochromatic ray of light PO is incident at the face of the prism A. Complete the diagram to show the path of the ray till it emerges out of the prism B.

Draw a diagram to show the refraction of a monochromatic light ray through an equilateral prism. On the diagram, label the incident, refracted, and emergent rays. It also indicates the angle of deviation by the letter δ.